For comparison, the researchers also interviewed the parents of 558 healthy children.
The study began in 1980, when the researchers interviewed 2,033 couples, age 55 and younger, by phone.
Ten months after the event, the researchers interviewed people about the crash.
The researchers interviewed people who had brought prescription drugs back from Mexico.
The researchers interviewed 400 parents in the Boston area about their knowledge of antibiotics.
For the study, researchers interviewed randomly selected participants by phone.
First, the researchers interviewed 240 young women with kidney infections.
Researchers interviewed some 3,000 women, about half of them diagnosed with breast cancer.
Twelve children had died from asthma attacks, so the researchers interviewed family members.
"When researchers went out and vigorously interviewed people, they found 40 percent had some sexual dysfunction."